Whole-Genome Analysis of 60 G Protein-Coupled Receptors in Caenorhabditis elegans by Gene Knockout with RNAi

Abstract

G protein-coupled receptors (GPCRs) are the largest family of genes in animal genomes and represent more than 2% of genes in humans and C. elegans. These evolutionarily conserved seven-transmembrane proteins transduce a diverse range of signals. In view of their pivotal role in cell signaling, it is perhaps surprising that decades of genetic analysis in C. elegans, and recent genome-wide RNAi screens, have identified very few GPCR mutants. Therefore, we screened all GPCRs predicted to bind either small-molecule neurotransmitters or neuropeptides by using RNAi and quantitative behavioral assays. This shows that C16D6.2, C25G6.5, C26F1.6, F35G8.1, F41E7.3, and F59C12.2 are likely to be involved in reproduction, whereas C15B12.5, C10C6.2, C24A8.4, F15A8.5, F59D12.1, T02E9.1, and T05A1.1 have a role in locomotion. Gene deletions for F35G8.1 and T05A1.1 resulted in the same phenotype as that seen with RNAi. As some GPCRs may be resistant to RNAi, or may result in abnormalities not screened for here, the actual proportion of nonredundant receptors with an assayable function is probably greater. Strikingly, most phenotypes were observed for NPY-like receptors that may bind neuropeptides. This is consistent with the known actions of neuropeptides on the body wall muscle and reproductive tract in nematodes.

RNA interference microarrays: High-throughput loss-of-function genetics in mammalian cells

“…High-throughput RNAi analyses have previously been used to study gene function in D. melanogaster and C. elegans. For example, essential genes (22), G protein-coupled receptors (GPCRs) (23), fat regulatory genes (24), and genes that regulate lifespan (25) have been functionally analyzed by this approach. Unfortunately, similar studies in mammals still represent a technological challenge.…”

UNC-73/Trio RhoGEF-2 Activity Modulates Caenorhabditis elegans Motility Through Changes in Neurotransmitter Signaling Upstream of the GSA-1/Gαs Pathway

“…Many neuropeptides and neuropeptide receptors are known to influence muscle and neuronal activity and ultimately locomotion in C. elegans and other nematodes (Marks et al 2001;Rogers et al 2001;Keating et al 2003;Husson et al 2007). It is possible that one or more neuromodulators required to regulate locomotion are released from neuronal DCVs in wild-type animals but are not transported properly through the neuronal secretory pathway in unc-73 RhoGEF-2 or rab-2 mutants and not properly released from unc-31 mutant neurons.…”

Functional characterization of the putative orphan neuropeptide G‐protein coupled receptor C26F1.6 in Caenorhabditis elegans

“…However, when reproduction is considered, Keating and coworkers [21] very recently found that RNAi of the presently identified VRFamide receptor 1 on N2 animals resulted in a statistically significant increase in the number of progeny counted 48 h post-L4. The precise mechanism underlying the RNAi effects on egg laying and brood size were not determined in the latter study.…”